INTERNATIONAL NETWORK FOR BAMBOO AND RATTAN (INBAR) TRANSFER OF TECHNOLOGY MODEL (TOTEM) BAMBOO PRESERVATION BY SAP DISPLACEMENT by Dr. K. Satyanarayana Rao Institute of Wood Science and Technology (IWST), Bangalore 560 003, India CONTENTS TRANSFER OF TECHNOLOGY MODELS (TOTEMs) 3 BAMBOO PRESERVATION BY SAP DISPLACEMENT AT-A-GLANCE 5 PART ONE: INTRODUCTION 1. Bamboo preservation by sap displacement 7 2. History of the development of sap displacement methods 7 3. General development attributes and advantages 7 4. Suitable agro-ecological regions 9 5. Target groups 9 6. Benefits 10 7. Scope for small enterprise development 10 8. Requirements for success 11 Concluding remarks 11 PART TWO: BAMBOO PRESERVATIO BY SAP DISPLACEMENT 1. Introduction 13 2. Production of preservative-treated bamboo 13 2.1 Raw materials 13 2.2 Preservatives 13 2.3 Treatment 14 2.3.1 Simple sap displacement technique 14 2.3.2 Modified Boucherie technique 14 2.4 Stacking 16 2.5 Safety precautions 16 3. Input requirements 17 Appendices 19-23 INBAR - IWST 2 Transfer of Technology Model: Bamboo Preservation by Sap Displacement TRANSFER OF TECHNOLOGY MODELS (TOTEMS) Transfer of Technology Models (TOTEMs) are focussed educational tools providing relevant information and distance training on one specific area of bamboo/rattan management, processing or utilization. They are a means of technology transfer between similar regions throughout the world, with the emphasis on South-South transfer for livelihood development. They enable those involved in the management and use of bamboo and rattan resources to more efficiently and effectively develop and use skills relating to these resources. TOTEMs are primarily intended as practical information resources and teaching aids for those at the local extension level in their communities, who can utilize them to assist local community development. Each TOTEM consists of a detailed written report of the technology, a PowerPoint presentation, a film, and, where relevant, a set of technical photographs. They also include information on target users, financial analyses of sample set-ups from the partner country preparing the report and information on where to source particular technologies (such as equipment). The TOTEM thus provides all the information required for establishing similar technologies within interested countries and regions. • The report contains all the technical details of the particular processes involved, as well as other relevant information for establishing the technology such as costs of business establishment, running costs and cash flows. • The PowerPoint presentation contains details of the relevant technologies and their applications, and is intended to provide an overview of the potential of the technology for development. • The film provides a visual guide to the processes involved and helps to bring them alive in the minds of the learners. The different parts of the TOTEM are targeted at slightly different audiences, via the local extension workers. The report and film are intended to be the main means of extension to the individuals and communities who will implement the technology and who will directly benefit from it. The PowerPoint presentation is primarily intended as a tool for the extension worker to sell the technology and its role in development to those who provide the infrastructural, policy and financial support for its implementation, such as government departments, donors and NGOs. There is considerable flexibility, however. Local extension workers will be able to incorporate the TOTEMs in their own work as they wish and adapt and develop the TOTEM to suit their particular requirements and conditions. This TOTEM on the bamboo preservation by sap displacement has been produced by the Institute of Wood Science and Technology (IWST), Bangalore, India. It may be used alone or in conjunction with the TOTEM on traditional bamboo preservation techniques, which has been produced by the Forest Research Institute, Dehra Dun, India. The report section of this TOTEM describes the technology of preserving bamboos by sap displacement and establishing facilities to INBAR - IWST 3 Transfer of Technology Model: Bamboo Preservation by Sap Displacement do so for rural development in regions where bamboo is available as a raw material. It is intended to be used in conjunction with the illustrative film included in this TOTEM package The first part of the report introduces the technology, discusses its history, its development attributes, its benefits and it’s applicability. The second part of the report provides detailed information on the technical aspects of sap displacement. Appendix I gives information on a practical demonstration of the technology in India. Appendix II illustrates the economic benefits of using treated bamboo compared to untreated bamboo. Appendix III is a bibliography of relevant publications and information used in the production of this report. This TOTEM is one of the first to be produced by INBAR/ IWST and your feedback is most welcome - kindly contact INBAR or IWST with your comments or suggestions. © International Network for Bamboo and Rattan 2001 Note: This TOTEM has been edited at INBAR and differs from the form in which it was received from IWST. INBAR - IWST 4 Transfer of Technology Model: Bamboo Preservation by Sap Displacement BAMBOO PRESERVATION BY SAP DISPLACEMENT AT-A-GLANCE Why preserve bamboos? Bamboos are a natural material and under natural conditions will gradually decay. If they are used as structural components they will need to be replaced after a period of time. The costs of this may prove prohibitive and the status of the bamboo will need constant monitoring to determine when it needs to be replaced. Preserving bamboos extends their life, reduces costs in the long run and improves safety of the structures they are used to form. What are sap displacement preservation methods? Sap displacement methods replace the sap in the vessels of a fresh bamboo culm with preservative. The culms are then left to stand for two weeks in order that the preservative can diffuse into the surrounding tissues and the preserving salts can be fixed in the cells. Sap displacement can be done by using natural capillary action or by one of a small range of simple pressurised techniques. What is the role of a sap displacement preservation unit in rural development? The unit itself offers employment opportunities to its employees and to many people in its forward and backward linkages. The unit can only treat freshly harvested bamboos and so a source of bamboos near to the unit is required. Local bamboo plantations can be established to supply the unit and create further income generating opportunities. Bamboos can be intercropped with food plants and the plantations can thereby increase the food security of the rural people that manage them. How do I establish a sap displacement unit? A sap displacement preservation unit can be established very cheaply. The only requirements are a supply of freshly harvested bamboos, labour and information from the secondary processors of their requirements. If a pressurised unit is to be established then a source of energy for the compressor will be needed. A pressurised unit capable of treating 50 bamboos per day can be established for USD $500, including a compressor, and non-pressurised units can be established for considerably less. INBAR - IWST 5 Transfer of Technology Model: Bamboo Preservation by Sap Displacement PART ONE INTRODUCTION DEVELOPMENT ATTRIBUTES, TARGET GROUPS and BENEFITS of a BAMBOO SAP DISPLACEMENT PRESERVATION UNIT INBAR - IWST 6 Transfer of Technology Model: Bamboo Preservation by Sap Displacement 1. Bamboo preservation by sap displacement Bamboo is a natural material and will decay with time. Decay occurs because of the high cellulose and lignin content of the culm. The strength properties of the culm will therefore change over time and eventually it may become so decayed as to be structurally unsound and even highly dangerous in the role to which it has been put. If used in the frameworks of buildings it could even render them uninhabitable. Bamboo culms are also susceptible to attack by biological agents such as boring insects, termites and fungi that can cause massive, sudden and catastrophic deterioration in structural soundness. The attraction of bamboos to insects appears to be due to their starch content and it is claimed that water-soaked bamboos, depleted of starch, resist insects better. The natural durability of bamboo is very low and depends on species, climate and age of the culm: Natural durability of some bamboo species (graveyard test data) Bamboo species. Maximum Minimum Average Information life life life source (months) (months) (months) Dendrocalamus 30 18 19.3 Unpublished data strictus FRI, Dehra Dun Dendrocalamus 21 9 13.0 Unpublished data membranaceous FRI, Dehra Dun Bambusa balcooa - - 32.0 Purushotham et al, 1954 Bambusa nutans 18 6 9.8 Unpublished data FRI, Dehra Dun Bambusa polymorpha 84 12 23.6 Unpublished data FRI, Dehra Dun Melocanna 24 9 19.9 Unpublished data bambusoides FRI, Dehra Dun Bambusa tulda - - 41.0 Purushotham et al, 1954 Source: Satish Kumar et al, 1994 Therefore it is essential to only use bamboo that has been preserved by proper preservative treatments. However, the preservative treatments applied to timber wood species are often not applicable to bamboo due to the different internal structure of the bamboo culm. Bamboo culms are divided into nodes and internodes and are composed of two types of tissue; parenchyma cells and vascular bundles. The latter consist of vessels, thick walled fibres and sieve tubes and it is through these that water movement takes place in the living plant. The vessels run straight along the length of the culm without INBAR - IWST 7 Transfer of Technology Model: Bamboo Preservation by Sap Displacement branching or any obstructing connections to single vessel members in the inner and outer part of the culm. Bamboo culms have no radial elements as in timber wood. The nodes, however, interrupt the easy transport of fluid.